Chapter 5- Biology

Question 1

3 components

Answer 1

Reception: message is transmitted via the extracellular environment of the cell and is detected by the cell.
Transduction: converts the message so that cellular response can occur
Response: physical, biochemical, physiological change in the cell

Question 2

Stimulus response model

Answer 2

Signal, Reception, Signal Transduction, Effector, Cellular Response

Question 3

Receptors on the cell surface

Answer 3

protein based ligands

Question 4

Intracellular receptors

Answer 4

in cytosol or nucleus- lipophilic

Question 5

Stages in Cell Comm

Answer 5

Cell migration (movement)
Cell division
Changes in cell metabolism
Apoptosis

Question 6

Signal transduction

Answer 6

Converts signal from outside the cell into a response within the cell. Signalling molecule binds to specific receptor, changes its 3D shape and activates it

Question 7

Transduction of lipophilic signals

Answer 7

Need carrier molecules when being transported through the blood,

Question 8

Path of hydophobic signals

Answer 8

• Signalling molecule passes through phospholipid bilayer
• Signal binds with receptor
• Signal-receptor complex moves from the cytoplasm into the nucleus
• Activated region of receptor protein attaches to a DNA region which then activates genes
• Relatively longer-lasting response
  e. g. steroids

Question 9

Hydrophillic siganls

Answer 9

• Includes peptide and protein hormones (eg’s?)
• Transported in solution in blood plasma
• Signalling molecule cannot enter the cell, it binds to a surface receptor
• A secondary messenger within the cell amplifies the message and a relay or cascade of messages (reactions) occurs
• The message reaches the nucleus where specific genes are activated
• Shorter period of response

Question 10

Hormone

Answer 10

A chemical messenger , secreted by specialised endocrine cells in one part of the body, and often travel via the bloodstream to a target organ/cell where it effects a response.

Question 11

Resting potential

Answer 11

cytoplasm has a slight negative charge compared with the extracellular fluid as K+ channels open and leave the cell.

Question 12

Action potential

Answer 12

exited neuron, positive cytoplasm. sodium ions flood into the cell

Question 13

Cytokines

Answer 13

cell signalling molecules that aid cell to cell communication in the immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma

Question 14

plant hormones

Answer 14

Animal hormones:

• chemical messengers
• only required in small quantities

Question 15

Different to animal hormones

Answer 15

mode of transport

-produced in meristems (growing regions)

Question 16

Necrosis

Answer 16

unplanned cell death,

• mechanical damage
• chemical trauma